Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 200226
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
826 PM MDT SUN OCT 19 2014

.SYNOPSIS...AN INCREASINGLY DRY AND MILD SOUTHWESTERLY FLOW WILL
DEVELOP MONDAY AHEAD OF A PACIFIC TROUGH WHICH WILL CROSS
NORTHERN UTAH TUESDAY. A SECONDARY WEATHER DISTURBANCE COULD
GENERATE ADDITIONAL SHOWERS ACROSS THE NORTH MIDWEEK. HIGH
PRESSURE ALOFT WILL FOLLOW FOR LATE IN THE WEEK.

&&

.SHORT TERM (THROUGH 00Z THURSDAY)...LINGERING SHOWERS ALONG THE
WEAKENING DEFORMATION AXIS OVER SOUTHWEST UTAH SHOULD DISSIPATE
BEFORE MIDNIGHT. SKIES HAVE CLEARED ACROSS THE NORTHERN TWO-THIRDS
OF THE STATE...WITH THE REMAINING CLOUD COVER ACROSS THE SOUTH
THINNING OUT LATER THIS EVENING.

THE UPPER RIDGE AXIS CURRENTLY ACROSS THE EASTERN GREAT BASIN
THROUGH THE NORTHERN ROCKIES WILL SHIFT EAST INTO THE PLAINS
STATES EARLY THIS WEEK. AN INCREASINGLY WARM AND DRY SOUTHWEST
FLOW ALOFT WILL DEVELOP ACROSS THE GREAT BASIN AHEAD OF AN
ADVANCING PACIFIC TROUGH ON MONDAY. THIS TROUGH WILL MAINTAIN
FAIRLY GOOD BAROCLINIC STRUCTURE AS IT MOVES INLAND MONDAY NIGHT.

THE STRONG HIGH AMPLITUDE RIDGE OVER THE CENTRAL CONUS WILL SERVE
TO DEFLECT THE TROUGH TO NORTHEAST WITH THE CORE OF THIS FEATURE
TRACKING THROUGH THE NORTHERN ROCKIES AND NORTHERN GREAT BASIN ON
TUESDAY. THIS TRAJECTORY WILL TAKE THE SOUTHERN END OF THE TROUGH
ACROSS THE FAR NORTHERN PORTION OF UTAH TUESDAY AFTERNOON THROUGH
EARLY EVENING.

THE SURFACE COLD FRONT SHOULD REMAIN FAIRLY WELL DEFINED AS IT
MOVES ACROSS NORTHERN NEVADA DURING THE DAY. THE BIG QUESTION
WILL BE HOW MUCH AND HOW FAST THIS FRONT WEAKENS AS IT PRESSES
EAST THROUGH NORTHERN UTAH WHILE THE CORE OF THE TROUGH LIFTS OFF
TO THE NORTHEAST. FOR NOW IT APPEARS THAT ENOUGH LOW-LEVEL COLD
ADVECTION WILL EXIST TO GENERATE LIFT...WITH MODEST MID-LEVEL
COOLING BRINGING A PERIOD OF CONVECTIVE INSTABILITY ACROSS THE
NORTHERN THIRD OF THE STATE TUESDAY NIGHT. A SECONDARY SHORTWAVE
TRAILING THE FIRST TROUGH WILL CROSS THE NORTH WEDNESDAY. THIS
FEATURE SHOULD BE ABLE TO UTILIZE THE LINGERING MOISTURE TO
GENERATE A FEW ADDITIONAL SHOWERS ACROSS THE NORTHERN HALF OF THE
STATE THROUGHOUT THE AFTERNOON HOURS.

&&

.LONG TERM (AFTER 00Z THURSDAY)...A FEW CHANGES TO NOTE IN GLOBAL
GUIDANCE FOR THE LATTER PERIODS. RIDGE AMPLIFICATION ACROSS THE
EASTERN GREAT BASIN IS NOT AS PRONOUNCED AS EARLIER RUNS BUT WILL
REMAIN DOMINANT HEADING INTO THE WEEKEND. GFS HAS BEEN KEYING INTO
THIS AT TIMES OVER THE LAST FEW DAYS BUT NOW BOTH IT AND THE ECMWF
SHOW SIMILAR OUTPUT REGARDING A POTENTIAL UPSTREAM SHIFT IN THE
PATTERN AS THE EASTERN PACIFIC LONG WAVE TROUGH APPEARS TO BE A BIT
MORE PROGRESSIVE...SHIFTING INLAND LATE NEXT WEEKEND. THOUGH TIMING
REMAINS OFF BY 24 HOURS REGARDING INITIAL IMPACTS OF A POTENTIALLY
POTENT FALL TROUGH...00Z SUN GFS VS. 00Z MON ECMWF...CONFIDENCE IS
TRENDING TO GROW REGARDING A PATTERN SHIFT OCCURRING LATE IN THE
FORECAST PERIOD.

MAINTAINED DRY AND UNSEASONABLY WARM CONDITIONS THROUGH
SATURDAY...AS RIDGE POSITIONS OVERHEAD THEN SHIFTS EAST ALLOWING
STRENGTHENING SOUTHWESTERLY FLOW ALOFT TO DEVELOP. ADDED SLIGHT
CHANCE POPS FOR DAY 7 AND BEGAN A TREND TO LOWER SNOW LEVELS/TEMPS
SUNDAY DUE TO POTENTIAL OF TROUGH NOSING IN BY THEN.

&&

.AVIATION...VFR CONDITIONS WILL EXIST UNDER CLEAR SKIES THROUGHOUT
THE TAF PERIOD. LIGHT SOUTHEAST WINDS WILL DEVELOP BETWEEN 03-04Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&

$$

CONGER

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)


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